WO2015158457A2

WO2015158457A2 - Switching device for a wye-delta switch in a multiphase motor

Info

Publication number: WO2015158457A2
Application number: PCT/EP2015/054154
Authority: WO
Inventors: Ingo Schaar
Original assignee: Eaton Electrical Ip Gmbh & Co. Kg
Priority date: 2014-04-17
Filing date: 2015-02-27
Publication date: 2015-10-22
Also published as: CN106233611A; CN106233611B; CA2945545A1; US20170032916A1; US10283297B2; EP3132534A2; WO2015158457A3; DE102014105579A1

Abstract

The invention relates to a switching device for a wye-delta switch in a multiphase motor with one motor winding per phase, each motor winding comprising a motor winding connection pair (U1, U2, V1, V2, W1, W2), and the switching device comprising the following: an electromagnetic drive (10, 11) for moving a drive axle (12) between three defined axial positions (14, 16, 18), and one contact device (20) per motor winding, said contact device comprising a first and a second motor winding connection contact (22, 24), a phase connection contact (26), and a movable contact bridge (28) that is coupled to said drive axle (12) and can be moved by same into the three defined positions (14, 16, 18). In a first position (14), lying axially between the two other positions, the movable contact bridge (28) is in an open position where none of the connection contacts (22, 24, 26) is electrically connected to any of the other connection contacts (22, 24, 26) by the contact bridge (28); in a second (16) of the three defined positions, said moveable contact bridge (28) is in a 'wye' contact position where the contact bridge (28) electrically connects the phase connection contact (26) to the first motor winding connection contact (22), and the second motor winding connection contact (24) is electrically connected to the second motor winding connection contacts of all of the other contact devices by means of a 'wye' contact (30) that is coupled to the drive axle (12); and in a third (18) of the three defined positions, the moveable contact bridge (28) is in a 'delta' contact position where said contact bridge (28) electrically connects the phase connection contact (26) to the first and the second motor winding connection contacts (22, 24).

Description

Switching device for a star-delta switching at a

multi-phase motor

The invention relates to a switching device for a star-delta switching in a multi-phase motor.

A star-delta switchover is used, for example, for starting up 3-phase (electric) motors. In order to limit the high starting current, the three motor windings are connected during a start-up phase of the motor to a star connection in which the three phases L1 to L3 for the power supply of the motor connected to the terminals U1, V1 and W1 of the motor windings and the terminals U2, V2 and W2 are interconnected. This interconnection reduces the overall power of the engine when starting up to one third of the operating power. In operation, the motor windings are connected in a triangle by the terminals U1, W2 and V1, U2 and W1, V2 are connected together and connected to the phase L1 and L2 or L3.

As shown in FIG. 1, three contactors Q1 1 (line contactor), Q12 (delta contactor) and Q13 (star contactor) are used to implement such a star-delta changeover. The contactors Q12 and Q13 realize the star-delta switchover. For the star connection, the contactor Q13 is closed, and the contactor Q12 is opened. For the delta connection it is vice versa. In order to avoid short circuits between the phases L1, L2 and L3 during the switching by a simultaneous switching of the contactors Q12 and Q13, these contactors are locked against each other, which is ensured by auxiliary contacts.

From the patent DD268569A1 a switching device for a star-delta contactor is known, in which three contact levels are provided so that network, - can be integrated with a time relay and star contactor in an assembly. The star-delta switchover takes place via a bimetal, which unlocks a mechanical lock and the contactor of the star and the Triangular operation forces when the network level contacts are closed. However, a bimetal is not very accurate, so the switching timing from the star to the delta connection can not be determined accurately. In addition, many springs are used to build up the force to hold the contacts in position or bring in this known construction. Since the elasticity of the springs can decrease over time, this suffers the reliability of the switching device.

The international patent application WO00 / 57444A1 also describes an integrated star-delta switching device comprising two contactor drives in the form of coils, by means of which a lever can move movable, spring-held contacts between two positions in order to switch from star to delta. However, this lever design is structurally complex and also requires many springs with the aforementioned disadvantages. In addition, two contactor drives are required.

Object of the present invention is therefore to provide an improved switching device for a star-delta switching in a multi-phase motor.

This object is solved by the subject matters of the independent claims. Further embodiments of the invention are the subject of the dependent claims.

An underlying idea of the present invention is to provide a contact device per motor winding of a polyphase motor, which is designed such that it integrates the switching functions of the mains, delta and star contactors and has a contact bridge coupled to a drive axis of an electro-magnetic drive , which can be moved via the drive axle between three defined axial positions. In this case, in the contact device no springs for force build-up or for holding the contact bridge is required because their position or axial position can be controlled precisely with the electro-magnetic drive. In addition, the switching process and time can be exactly controlled by the electromagnetic drive from star to delta circuit and vice versa An embodiment of the invention relates to a switching device for a star-delta switching in a polyphase motor with a motor winding per phase, each motor winding each having a motor winding terminal pair U1, U2, V1, V2, W1, W2, and wherein the switching device following comprising: an electro-magnetic drive for moving a drive axis between three defined axial positions and per motor winding a contact device having a first and a second motor winding terminal contact, a phase terminal contact and a movable contact bridge, which is coupled to the drive axle and via this in the three defined positions can be moved. The movable contact bridge is located in a first and axially located between the other two positions position in an open-Steil, in which none of the terminals is electrically connected to another of the terminal contacts via the contact bridge. In a second of the three defined positions, the movable contact bridge is in a star contact position, in which the contact bridge electrically connects the phase connection contact with the first motor winding connection contact and the second motor winding connection contact via a star contact coupled to the drive axis the second motor winding terminal contacts of all other contact devices is electrically connected. And in a third of the three defined positions, the movable contact bridge is in a triangular contact position in which the contact bridge electrically connects the phase terminal contact to the first and second motor winding terminal contacts.

In particular, the contact device may comprise: a conductive contact arm emanating from the first motor winding terminal contact and extending to the level of the star contact position, which is contacted by the contact bridge in the star contact position; a conductive contact arm extending from the first motor winding terminal contact and extending to the level of the triangle contact position contacted by the contact bridge in the triangular contact position; a conductive contact arm extending from the phase termination contact and extending to the level of the star contact position contacted by the contact bridge in the star contact position; a conductive contact arm extending from the phase termination contact and extending to the level of the triangular contact position, the contact arm in the Triangle contact position is contacted; and a conductive contact arm extending from the second motor winding terminal contact and extending to the level of the triangle contact position contacted by the contact bridge in the triangular contact position and the star contact in the star contact position. The two conductive contact arms respectively starting from the first motor winding connection contact and from the phase connection contact may form a U or V, other contact points are provided at each other, to which corresponding contact points of the contact bridge for contacting in the corresponding position of the contact bridge are pressed. The electro-magnetic drive may comprise a movable permanent magnet coupled to the drive axle and a fixed electromagnet. The movable permanent magnet can be held by springs in the de-energized state of the fixed electromagnet in a first position, so that the drive axle is in the first defined position, and the movable permanent magnet can in the energized state of the fixed electromagnet depending on the current direction in a second or a third position against the force of the springs are pressed against a stop or on poles of the fixed electromagnet, so that the drive axle is in the second or third defined position. Alternatively, the electro-magnetic drive may also have a movable electromagnet coupled to the drive axle and a fixed electromagnet. In this case, the movable electromagnet can be held by springs in the de-energized state of the movable or fixed electromagnet in a first position, so that the drive axle is in the first defined position, and the movable electromagnet can in the energized state of both electromagnets depending on the current direction in a second or third position against the force of the springs are pressed against a stop or to poles of the fixed electromagnet, so that the drive axle is in the second or third defined position. The springs can be provided here as electrical leads for energizing the movable electromagnet. The contactor may also include semiconductor switches connected between the movable contact bridge and the first and second motor winding terminal contacts and the phase terminal contact.

Further advantages and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments illustrated in the drawings.

In the description, in the claims, in the abstract and in the drawings, the terms and associated reference numerals used in the list of reference numerals recited below are used. The drawings show in

1 shows a conventional star-delta switching in a three-phase motor with three contactors.

Fig. 2 is a sectional view of an embodiment of a contact device of a switching device according to the invention; Fig. 3 shows a first embodiment of an electro-magnetic drive with a movable permanent magnet of a switching device according to the invention; and

Fig. 4 shows a second embodiment of an electro-magnetic drive with a movable electromagnet of a switching device according to the invention.

In the following description, identical, functionally identical and functionally connected elements may be provided with the same reference numerals. Absolute values are given below by way of example only and are not to be construed as limiting the invention.

The switching device for a star-delta switching in a 3-phase motor with a motor winding per phase according to the invention integrates the three contactors Q1 1, Q12 and Q13 of the conventional star-delta switching shown in Fig. 1 by a special contact device 20th , from the in Fig. 2 a Section view is shown. For this purpose, a separate contact device 20 is provided per motor winding, so that three of the contact device 20 shown in FIG. 2 are required in the 3-phase motor.

The contact device 20 is characterized in particular by the fact that the axially movable (see the double arrow in Fig. 2) movable contact bridge 28 in three defined and different positions can be moved: an open position or - position 14 (middle position of the contact bridge as 2), a star contact position 16 and a triangle contact position 18. The three positions 14, 16, 18 correspond to three different planes.

The contact bridge 28 is axially moved between the three axial positions 14, 16 and 18 via a drive shaft 12 connected to it made of a non-electrically conductive material, in particular an insulator. The movement takes place via an electromagnetic drive. As shown in FIG. 2, the contact device 20 does not require springs for holding the contact bridge 28 in its three positions 14, 16, 18.

The contact device 20 shown in FIG. 2 has a first motor winding connection contact 22, a second motor winding connection contact 24 and a phase connection contact 26. In the first of the three contact devices, the connection contact 22 is connected to U1, the connection contact 24 to V2 and the connection contact 26 to L1. In the second of the three contact devices, the connection contact 22 is connected to V1, the connection contact 24 to W2 and the connection contact 26 to L2. In the third of the three contact devices, the connection contact 22 is connected to W1, the connection contact 24 to U2 and the connection contact 26 to L3. From the terminal contact 22 extend two electrically conductive contact arms 44 and 46 to the plane of the star contact position 16 and the triangular contact position 18. As shown in Fig. 2 form the contact arms 44 and 46 in section about a U. Similarly, extending from the terminal contact 26 of two electrically conductive contact arms 48 and 50 in the plane of the star-contact position 16 and the triangular contact position 18 and form - as shown in Fig. 2 - in section also about a U. In the space surrounded by the contact arms 44, 46, 48 and 50, the contact bridge 28 is arranged in the star contact position 16 against the contact arms 44 and 48 and in the triangular contact position 18 against the contact arms 46th and 50 is pressed. Another electrically conductive contact arm 52 extends from the terminal contact 24 to the plane of the triangle contact position 18. As shown in Fig. 2, this contact arm 52 is provided at its end with a double contact, whereby the terminal contact 24 in the star contact Position 16 is contacted by a fixed to the drive shaft 12 star contact 30 and in the triangular contact position 18 of the contact bridge 28. If the contact bridge 28 is thus moved from the open position 14, in which none of the connection contacts 22, 24 and 26 is connected to another contact, into the star contact position 16, the connection contacts 22 and 26 are electrically connected to one another (ie U1 and L1, V1 and L2, W1 and L3), and the terminal contact 24 with the star contact 30, which is electrically connected to the star contacts of the other contact devices (ie V2 with W2 and U2). Thus, the star contact position 16 corresponds to the closing of the contactors Q1 1 and Q13 in the circuit shown in FIG.

In the triangular contact position 18, the contact bridge 28 closes all three connection contacts 22, 24 and 26 electrically short (ie U1 with L1 and V2, V1 with L2 and W2, W1 with L3 and U2). Thus, the triangle contact position 18 corresponds to the closing of the contactors Q1 1 and Q12 in the circuit shown in FIG.

Due to the design of the contact device 20 is always connected via the open position 14 of the star contact position 16 in the triangular contact position 18 and vice versa, no short circuits between the phases L1, L2 and L3 can occur.

Fig. 3 shows an electromagnetic drive 10 for the drive shaft 12 with a movably mounted and fixed to the drive shaft 12 permanent magnet 32 which is held by springs 36 in a first position between stops 38 and poles 40 of a fixed electromagnet 34, provided the electromagnet 34th is de-energized and exerts no magnetic force on the permanent magnet 32. In the first position of the permanent magnet 32 is the coupled with the drive shaft 12 contact bridge 28 in the open position 14. By appropriate energization of the fixed electromagnet 34 (voltage U1 in Fig. 3), the permanent magnet 32 can be attracted or repelled by the electromagnet 34 , In order to move the contact bridge 28, which is coupled to the drive axle 12, into the star contact position 16, the electromagnet 34 is energized in such a way that the permanent magnet 32 is repelled and pressed against the stops 38. In order to move the contact bridge 28, which is coupled to the drive axle 12, into the triangular contact position 18, the electromagnet 34 is energized so that the permanent magnet 32 is attracted and pressed onto the poles 40.

Instead of a permanent magnet 32 and a movable electromagnet 42 may be used, such as the electro-magnetic drive 1 shown in FIG. The energization of the movable electromagnet 42 can take place via the springs 36 (voltage U2 in FIG. 4) in order to avoid additional electrical lines.

Should the transitions between the individual positions 14, 16 and 18 be problematic with respect to arcing, semiconductor switches can be connected between the movable contact bridge and the terminal contacts 22, 24 and 26 which are turned on to prevent arcing when the contacts 22, 24 and 26 are opened become.

The switching device according to the invention could, for example, be controlled as follows: a timer could be used to specify a time after which the operating mode should be changed, for example, from a star to a delta circuit. The switching can also make a control that controls the electro-magnetic drive accordingly. Since no auxiliary switches as in the conventional star-delta switching shown in Fig. 1 must be queried, the programming effort for a control of the switching can be significantly reduced with the invention. As a further alternative, a predetermined electrical voltage could be checked, for example with ramp function, to distinguish between the switching states. The Schaltvornchtung invention is particularly suitable for use in motor starters. The switching device according to the invention only requires the connection of the motor and the phases of the three-phase power supply. The electromagnetic drive of the switching device according to the invention can optionally be controlled by a memory programmable controller (SPS) or by simply applying an electrical voltage. The switching device according to the invention allows a compact design due to its high functional density. Finally, the switching device according to the invention allows a reduction of the material costs in production, since only an electromagnetic drive, only an electronics for driving, no pre-wiring of multiple contactors in production and only one housing are required.

Reference numeral electro-magnetic drive with permanent magnets electro-magnetic drive with electromagnet drive axle made of non-conductive material

Open position

Star-contact position

Triangle contact position

contact device

first motor winding connection contact

second motor winding connection contact

Phase terminal contact

movable contact bridge

Star contact

movable permanent magnet

fixed electromagnet

feathers

attack

Pole of the fixed electromagnet

moving electromagnet

conductive contact arm

Claims

claims

1 . Switching device for a star-delta switching at a

multi-phase motor with one motor winding per phase, each one

Motor winding each having a motor winding terminal pair (U1, U2, V1, V2, W1, W2), and wherein the switching device comprises

- An electro-magnetic drive (10, 1 1) for moving a

Drive axle (12) between three defined axial positions (14, 16, 18) and

- Per motor winding a contact device (20) having a first and a second motor winding terminal contact (22, 24), a phase connection contact (26) and a movable contact bridge (28) which is coupled to the drive axle (12) and via this in the three defined positions (14, 16, 18) can be moved,

- wherein the movable contact bridge (28) in a first and axially

between the two other positions lying position (14) is in an open position in which none of the terminal contacts (22, 24, 26) is electrically connected to another of the terminal contacts (22, 24, 26) via the contact bridge (28) .

- wherein the movable contact bridge (28) is in a second (16) of the three defined positions in a star-contact position, in which the contact bridge (28) the phase connection contact (26) with the first motor winding connection contact (22 ) and the second motor winding connection contact (24) is electrically connected to the second motor winding connection contacts of all other contact devices via a star contact (30) coupled to the drive axis (12), and wherein the movable contact bridge (28) is in a third (18) of the three defined positions is in a triangular contact position, in which the contact bridge (28) electrically connects the phase terminal contact (26) to the first and second motor winding terminal contacts (22, 24).

2. Switching device according to claim 1, characterized in that

Contact device (20) comprises:

- a conductive contact arm (44) extending from the first motor winding terminal contact (22) and reaching the star contact position (16), contacted by the contact bridge (28) in the star contact position (16);

a conductive contact arm (46) extending from the first motor winding terminal contact (22) and extending to the level of the triangle contact position (18) contacted by the contact bridge (28) in the triangular contact position (18);

- one of the phase terminal contact (26) outgoing and to the level of the star contact position (16) reaching conductive contact arm (48) which is contacted by the contact bridge (28) in the star-contact position (16);

- a conductive contact arm (50) extending from the phase termination contact (26) and extending to the level of the triangle contact position (18) contacted by the contact bridge (28) in the triangular contact position (18); and

one from the second motor winding terminal contact (24)

outgoing and to the level of the triangular contact position (18) reaching conductive contact arm (52) of the contact bridge (28) in the triangular contact position (18) and the star contact (30) in the star contact position (16) is contacted.

3. Switching device according to claim 1 or 2, characterized in that the electro-magnetic drive (10) one with the drive axle (12)

coupled movable permanent magnet (32) and a fixed electromagnet (34), wherein the movable permanent magnet (32) by springs (36) in the de-energized state of the fixed electromagnet (34) is held in a first position, so that the drive axle (12 ) is in the first defined position, and the movable one

Permanent magnet (32) in the energized state of the fixed

Electromagnet (34) is pressed depending on the current direction in a second or a third position against the force of the springs (36) to a stop (38) or to poles of the fixed electromagnet (34), so that the drive axle (12) is in the second or third defined position.

4. Switching device according to claim 1 or 2, characterized in that the electro-magnetic drive (1 1) one with the drive axle (12)

coupled movable electromagnet (42) and a fixed electromagnet (34), wherein the movable electromagnet (42) by springs (36) in the de-energized state of the movable or

fixed electromagnet (34, 42) is held in a first position, so that the drive axle (12) is in the first defined position, and the movable electromagnet (42) in the energized state of both

Electromagnets (34, 42) depending on the current direction in a second or a third position against the force of the springs (36) to a stop (38) or to poles of the fixed electromagnet (34) is pressed, so that the drive axle ( 12) is in the second or third defined position.

5. Switching device according to claim 4, characterized in that the springs (36) as electrical leads for energizing the movable

Electromagnets (42) are provided. Switching device according to one of claims 1 to 5, characterized

characterized in that the contact device (20) comprises semiconductor switches connected between the movable contact bridge (28) and the first and second motor winding terminal contacts (22, 24) and the phase terminal contact (26).